In general, 3D image display techniques create a 3D effect of an object using binocular parallax as the most important factor that causes the 3D effect at a short distance.
Such 3D image display devices are generally divided into stereoscopic 3D image display devices and autostereoscopic 3D image display devices depending on the use of special glasses.
The stereoscopic 3D image display device requires a viewer to wear special glasses, which is inconvenient for the viewer, but in the case of the autostereoscopic 3D image display device, the viewer can feel the 3D effect only by directly viewing a screen, by which the drawbacks of the stereoscopic 3D image display device can be obviated. Accordingly, extensive research on the autostereoscopic 3D image display device has been conducted, and new products have recently been released.
The autostereoscopic 3D image display devices are generally divided into a lenticular method and a parallax-barrier method.
The lenticular method refers to a method of vertically arranging cylindrical lenses, in which a left image and a right image in units of vertical cells (R, G and B) are alternately arranged in the vertical direction (vertical interlace method) and specifically-designed refractive lenses are mounted in front of the left and right images, respectively, to separate the left and right images, thus providing a 3D image.
The parallax-barrier method refers to a method of dividing pixels of a display panel into left-eye pixels and right-eye pixels in units of R, G and B pixels (vertical interlace method) and providing a barrier substrate at each point corresponding to a gap between the left-eye pixels and the right-eye pixels at a predetermined distance from the left-eye pixels and the right-eye pixels such that the left-eye image is viewed only by a left eye and the right-eye image is viewed only by a right eye, thus reproducing the 3D image.
As such, the viewer feels the protrusion or depth of the image by combining the left and right images input to the left and right eyes, and thus it is difficult to quantify the depth of the 3D image as an objective numerical value.